Double-acting shock brake



.Dern 28,. v1943.v

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Dec 28, 1943- N. A. cHRlsTENsN 2,337,738

DOUBLE ACTING SHOCK BRAKE Filed Oct. 3, 1939 s sheets-sheet 2 .INVENTOR M625 Q /e/ra/.sa/ Y ATTORNEY.

Dc. 28, 1943. N A, CHRlsTENsEN 2,337,738

DOUBLE ACTING SHOCK BRAKE Filed but. :5. 1959 l sheets-sheet s INVEN I OR.

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Petenfed Dee. 2s, 1943 UNITED STATES PATENT OFFICE 2,937,738 DoULE-Ac'rma snoox BRAKE 4 Niels A. Christensen, South Euclid, Ohio Application october 3, 1999, serial No. 297,720

4 Claims.

This invention relates to new and useful improvements in shock brakes or shockeliminators.

An important object of the invention is to provide simple and reliable shock brakes, economical in production, readily installed and adjustable for climatic conditions and viscosity variations of its fluid working mediums, one of which is a fluid not materially affected by ordinary atmospheric temperatures.

Another object is to provide a shock brake which is readily adjustable for the travel of its piston in both directions, to provide a restrictive passage for the uid in passing from one sidev of the piston to the opposite side thereof and to include an improved form of packing requiring no adjustment during its life and which requires renewal only after long periods of hard service.

Another object of the invention is to provide an improved mounting bracket for the shock brake which renders the same readily demountable and to provide a leverage for connecting the sprung and unsprung masses which will maintain its lubrication and is constructed and arranged to offer some degree of protection to the various bearings and parts against extraneous matter.

Another object of the invention is to use wrought construction fabricated of high tension material to reduce the weight of the shock brake and increase its life.

Another object of the invention is to provide a shock brake which is workable in any position and which has interchangeable parts for various -types for use on automotive vehicles, airplanes, artillery recoil, and other equipment requiri'ngla shock brake or shock eliminator.

A still further object of the invention is to provide improved valve mechanism for such of the application and wherein like numerals are employed to designate like parts throughoutthe 2-12 of Fig. 1.

Fig. 3 is asimilar section of the piston bearing taken on the line 3,-3 of Fig. 1.

Fig. 4 is a. transverse section on the line 4 4 of Fig. 2.

Fig, 5 is a transverse section of a shock brake detached from the supporting bracket and is taken on the line 5--5 of/Fig. 2.

Fig. 6 is a fragmentary cross section taken on the line 6-6 of Fig. 5.

Fig. 7 is a side elevation of the shock brake and lever system as applied to an automotive vehicle.

Fig. 8 is a top plan of the mounting bracket.

Fig, 9 is a top plan ofthe device shown in Fig. 7.

Fig. 10 is a longitudinal section'of another form of the invention Iillustrating the direct acting .type and is taken on the line A-A of Fig. 1l.

Fig. 11 is a top plan of the form of invention shown in Fig. 10.

Referring now more particularly to the form of invention shown in Figs. l, 2 and 9 inclusive, the numeral I designates a cylindrical` casing having its lower end closed by a cap 2 and its upper endy enlarged at 3 to provide an internal shoulder 4, To the exterior of this enlarged portion are welded a plurality ofthreaded studs 5 projecting longitudinally and weli'beyond 'the end of the casing ,for a. purpose described, y

A packing gland composed of a pair of rings 6 of Lsection,one I of Z-section and another 8 of rectangular section are superimposed and placed'- as a lunit inside of the enlarged end 3 of the cylinder and against the shoulder 4.- The rings of L and Z sections provide inner peripheral` and slidably engages this packing gland and cylinderhead. Thehollow piston stem being smaller in diameter than the cylinder I, provides an annular fluid chamber I5. slidably mounted upon the walls of cylinder `I is a differential piston head I6, the'skirt of which is provided with a plurality ofv peripheral grooves to receive elastic composition packing rings I'I operating in accordance with my aforesaid patent to increase which will be hereinafter i 2B at the end-of the main cylinder I.

vis welded to the lower end of the piston sleeve'I3.

` This hub portion is provided with an axial openf ing I9 for connecting the inner chamber I4 with an end chamber 20 arranged between the end of I the piston head and the end closure 2. The piston headl is formed with two ports 2| and 22 connecting the annular space I with the chamber A valve seat 23 is formed in the port 2| to cooperate with the conical end of an adjusting rod 24 which extends through the piston sleeve I3 and through -a solid piston head 25 welded to the upper end of piston sleeve I3. The-upper exposed end of the adjusting rod 24 is screw threaded to receive a cap nut 26 provided with a copper washer 21 to form a tight joint after an adjustment of the rod has been made by turningthe cap nut. This adjustment of the valve rod 24 determines the degree of restriction of the passage of liquid from the annular chamber I5 on the upward or recoil stroke of the shock brake through port' 2l, and also servesP as a passage for liquid on the down stroke to restore the liquid to the annular chamber I5.

The other port 22 in the piston head threadedly receives a valve cage 28 provided with a valve seat 29 for` a ball valve 30. A light coil spring 3| positioned in the cage 28, normally urges the ball valve 36 ofi of its seat. During slight pulsations of the piston I3, this ball valve remains open and `liquid can pass through the port 22 but if a sudden upward piston motion takes place, dueto bumps in the road, the rush of liquid will cause the ball valve to compress its spring 3| and that the rofl aa' mayfteadlusted longitudinally to' LAadjust the lift of the ball valve. Thus, it will be `seen that the adjusting rods 24 and 33 may be readily adjusted from the exterior of the shock brake without taking the vehicle out of service.

For filling the` shock brake with liquid and compressed air, the piston cap is provided with an inclined port opening out through the cap between the two cap screws 26 and 34 as best 'seen in Fig. 1. A valve controlled filler plug 36 v is associated with the outer end of the port 35,

while the inner end of the port is screw threaded to receive a filler tube 31 extending axially through the pistn sleeve I3 to a point where a predetermined liquid level is to be maintained in the chambers I4 and I5. f

'I'he uppen end of the piston head is provided with a bearing sleeve 38 fora purpose which will b`e presently described. A dust boot 39 is fastened at one end to the piston cap and at its other end to the ycylinder head I0 for protection of the piston rod from road dirt.

The shock brake cylinder I is mounted upon the sprung mass by a U-shaped fabricated steel mounting bracket, having `a..horizontal top wall 40 and a pair of depending spaced parallel side walls 4I which arereinforced by a pair of transversely extending spaced apart cross bars 42 which are welded at their ends to the two vertical walls 4I. These side wails are also providedwith registering openings, between each pair of which, a reinforcing tube 43 is welded at'its ends to the spaced side walls as shown, to provide means through which bolts, not shown, may extend to fasten the mounting bracket upon the sprung mass 41. Due to the construction of the bracket, it may be used upon either side of the vehicle.

For securely and detachably connecting the shock cylinder I to the mounting bracket, the upper wall of the latteris provided with an enlarged opening 44 through which projects the upper endof the cylinder head I0. Surrounding this enlarged opening are a plurality of smaller bolt openings 45 in the'upper wall 40 to receive the upper threaded ends of the studs 5. Nuts 46 are threaded upon the projecting ends of the studs to rigidly clamp the shock cylinder to the wall of the bracket. The sprung mass in the particular illustration used herein for an example of the application of the shock brake, is shown at the 'side rail 41 of an automotive vehicle.

For connecting the shock brake to the unsprung mass of the automotive vehicle, herein shown as one of the axles 48 thereof, a fulcrum member 49 has its lower bearing end extending through a kerf or a slot 58 in the upper wall 40 of the mounting bracket and mounted upon a spindle 5I. The ends of this spindle extend through the side walls 4I of the mounting bracket and through bearing blocks 52 welded to the inner surfaces of the side walls. This spindle is releasably retained in its bearings by means of the lock bolts 55 as shown in Fig. 7. The spindle 5I is' provided with a pair of peripheral grooves `56, in which operate elastic packing rings 51 which bear 4upon the bearings in the lower end of the fulcrum 49 to seal the surfaces against the admission of dirt and to preclude leakage of lubricant furnished through the lubricating passage 58 extending longitudinally through' the spindle 5I to the end thereof, where it may be provided with ra suitable lubricating tting. These packing rings 51 are disclosed in my aforesaid patent and operate with equal efficiency Whether used in axially sliding contacts, or as in this instance, when they are used for oscillating movement.

The upper bearing end 60 of the fulcrum link 49 is straddledI between the depending arms of aV stamped lever 'or walking beam 6I and is mounted upon va fulcrum pin 82 fastened in lever 6I as shown. This fulcrum pin is also provided with the grooves 56 and packing rings 51 as well as the lubricating passage 53 which directs lubricant to theentire surface of the bearing 60 between the two packing rings.

The'lever 6I for the greater portion of its length is of inverted channel shape to cover and protect the parts with which it is connected. One end of this lever overlaps and covers the major portion of the piston head 25 as best seen in Figs. '1 and 9 and is pivotally connected thereto by means of a pivot pin 63 similar to the pin 62.

4This. pivot pin 63 is connected with the free end bali tting 64 which is connected to the upper end of a link 66 which is an ordinary SAE standthat as the piston I6 moves inwardly in cylinder I, the volumetric capacity of annular chamber I increases and that liquid from chambers I4 and 20 will flow freely upwardly into chamber-I5 through passage 32, around the valve 30 held open by compression spring 3|- and thence through port 22, as well as through the passages 2| and 23 at a rate depending upon the position of valve 24. Upon rebound of the vehicle axle 48, the piston I6 moves outwardly of the cylinder I and causes a `reduction in the volumetric caf said rods forming a needle valve with its portV pacity of annular chamber I5. On small shocks,

small displacement of piston I6 occurs, and the pressure in chamber I5 will not be suiiicient to seat the valve 30 against the tension of lspring 3|. However, when the vehicle encounters more severe shocks, the piston I6 will move upwardly I at increased speed, causing quicker reduction of volumetric capacity of chamber I5 and greater pressure thereinV to .overcome the spring 3| and to force the` valve 30 to close upon its seat Ito check the rebound according to the area'of passage 23 previously adjusted by the valve 24. It will be evident, of course, that the air above the liquid level in chambers |4 and I5 will cushion the shocks by being compressed and that the restriction in the flow of liquid from the annular chamber I5 to the chambers 20 and I4 will effectively check rebounds. It will also be apparent that the rate of flow of liquid into and out of the annular chamber I5 will be regulated as desired by adjustment of the rods 24 and 33 with consequent adjustment of the'amount of the clearance through ports 23 and 32.

Referring now to Figs. 10 and `1l, a construction of a direct acting shock brake is illustrated which eliminates the lever linkage, but requires more head room in its mounting. Most of the parts of this form 0f device are the same'as in the preceding form and corresponding numerals have been employed to designate corresponding parts. The piston head in this instance is provided with a. centering boss 'I0 for receiving a tubular housing 'II.d A similar boss and housing is provided for thev other end of the shock brake. These housings are welded to their respective cylinders and piston' parts and the spring plungers therein are the same as in SAE standard steering connections for receiving the ball studs 'I2 fastened to the two relatively movments controlled. It will of course be understood that in this form of device, the use ofthe mounting bracket 4| is unnecessary.

`It will of course be understood that various changes in the size, shape and relation'of vparts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A shock brakeA comprising a cylinder closed able parts. which are to have their relative movey at both ends, .a hollow piston extending through one closed end and defining an axial fluid chamber, said piston having an enlarged end operating in said cylinder and spacing the piston from the walls thereof to dene an annular fluid chamber, the outer end of the piston being closed, the inner end of said hollow piston having a pair of ports connecting the annular and axial chambers, a spring pressed normally unseated floating valve in one of said ports, and adjustable valve rods extending longitudinally through the piston from the exterior thereof intosaid ports, one of and the other forming a stop against which said floating valve is normally urged and held unseated. 4 Y

2. A shock brake comprising a cylinder closed at both ends, a hollow piston extending through one closed end to define an axial uid chamber and having an enlarged piston head operating in said cylinder and spacing the piston from the walls thereof to dene an annular fluid charnber, the outer end of the piston having a bearing member, the enlarged piston head having a pair of ports connecting the annular and axial chambers, a spring pressed normally unseated floating valve in one of said ports, valve rods slidably mounted through th bearing member to extend into said ports, one of said rods forming a needle valve with its port and the other rod forming a stop against which said floating valve is normally urged and held unseated, and, cap nuts threaded upon said rods and bearing against said bearing piston on one side of its axis to render the control means accessible for service adjustments without removal of parts.

4. A shock brake comprising a cylinder closed at one end and having a removable packed head at its other end, a hollow piston slidably mounted in said head and defining an axial fluid chamber, said piston' having an enlarged end operating in said cylinder and serving to space thehollow piston from the walls of said cylinder to define an annularfluid chamber at the sidesbf the piston and an end fluid chamber between the enlarged end of the piston and the closed end of said cylinder, the enlarged end of said piston having a pair of ports having seats connecting the annular and end chambers, a fixed adjustment valve in one port, and a full closing automatic valve normally resiliently urged off of the seat in said other port by a force suflicient to hold said valve unseated only during initial movement of the piston in a direction which would normally cause the valve to seat.

NIELS A. CHRISTENSEN. 

